The idiopathic nature of UCPPS has prompted an intense search for diagnostic and prognostic clinical biomarkers of this syndrome. The development of clinically relevant biomarkers of UCPPS is critical to effective clinical management and to the understanding of UCPPS pathology, and to the goal of advancing current treatment and developing novel therapies. During MAPP-I, we have taken advantage of the power of our interactive Trans-MAPP Network to successfully identify a panel of biologically-relevant, noninvasive urinary biomarkers of UCPPS using two distinct approaches: (1) a biologically-driven biomarker discovery strategy grounded in the basic biology and physiology of this disease and (2) a global proteomics biomarker discovery strategy. As members of the MAPP Biomarker Working Group, we exploited our own extensive experience in human sample repository development and biosampling, along with that of our colleagues, to develop the 'Best Practices' protocols that are currently being utilized for the acquisition, shipping and storage of all human samples in the MAPP network. Through our directed, biologically-driven studies, we have analyzed ~500 (to date) urine samples provided during MAPP-I for the presence and amounts of six different protein biomarkers identified as described above. In addition to the identification and validation of these individual protein biomarkers, we also found that (1) UCPPS significantly changes the urinary proteome as compared to that of healthy and positive controls and (2) UCPPS may alter the regulation of extracellular matrix proteins in a definable, biologically-relevant pattern. We are now in the process of completing the validation studies of those urinary proteins identified in our global proteomics work and intend to multiplex them with those discovered through our biologically-driven discovery studies. We will then combine our final validated panel of biomarkers with biologic and clinical data from other participating MAPP discovery sites. Multiplexing these markers will increase the predictive power of any of the markers alone. We will then test the ability of this panel of biomarkers to identify the presence o UCPPS, monitor response to therapy, predict disease progression and episodic flares, and confirm improvement and resolution, with or without intervention. Finally, we will ask what these validated diagnostic targets teach us about mechanism(s) underlying these different UCPPS disease stages. These goals will be met within the context of the following Specific Aims: Aim 1 To assess the utility of the identified and validated urinary biomarkers from Phase I in the clinical management of UCPPS Aim 2 To assess the clinical utility of multiplexing all biomarkers validated in our studies with biologic and clinical data identified and validated by other Trans-MAPP groups Aim 3 To elucidate the mechanism(s) underlying the presence of disease, disease flare, response to intervention and resolution